I'm currently trying to get down my LR and I've been practicing questions by type through Cambridge's study materials... and I've been noticing that I struggle with Weaken, Flaw, Principle, and Assumption types the most.

A couple questions:

For weaken type questions, does the answer choice HAVE to attack the conclusion directly? The PS LRB says that it does most of the time, but has anyone seen where it attacks the premise? Or are we aiming to break the link between the premise and the conclusion?

For the more difficult questions, I seem to be able to narrow down to like 2 choices then I fail. I know this is a really vague question, but for those who have experienced this in the past, what have you been missing out to get narrow down the final choice?

And if there are any surefire ways to eliminate answer choices, I'd appreciate any advice.e.g. such as like in parallel (flaw), where you eliminate the "most" "some" "all" choices if those terms aren't being used in the stimulus

I've heard practice practice practice as the general rule of thumb for LR. In addition, I also review my answer choices for the reasoning behind the correct/incorrect choices but I feel like it doesn't translate into better scores. Maybe I haven't done it enough?

Any advice from those who improved LR drastically? I've read a bunch of threads here on how to improve LR but I haven't yet come across something groundbreaking for myself. Right now I get anywhere from 2~5 wrong per LR. It really depends on luck for me it seems. I average closer to 3 per LR section, but like I said, I'd like to get these questions out of the way.

Also, I have those questions where I feel 100% confident, but I know that a lot of the questions (even the ones I get right) I feel like 80% confident in the answer then some other choice starts to make sense. It's a danger, but if anyone is out there that can understand what I mean, any advice on minimizing that would be crucial and of great help.

There's no magical "groundbreaking" solution that you are looking for. Look over your previous sections and see which type of questions you miss most. Go over the corresponding chapter in LRB then do a bunch of those question type. Go over your missed questions. I did nearly 50 full sections of LR before I started getting around the type of score I wanted for LR. There's only so many ways LSAC can word wrong answers, and only so many "tricks" they can use for different question types. Eventually you will be able to see wrong answers pretty clearly. Some people can figure it out by just doing a few sections, some people (like me) have to do dozens. If you put in quality time you will eventually see results.

As for weaken questions, there's always an assumption linking the premises and conclusion. Attack this assumption and you have the right answer. Your job is to show that the conclusion does not necessarily follow from the premises.